FR2779790A1 - Sequential gearbox gear selector - Google Patents

Abstract

The selector comprises a handle (3) that moves in a pendulum motion about a pivot (2). This is connected to the gear selection shaft by a two bar link pivoting at (1). The pendulum action of the handle causes the short member (4) of the two bar link to rotate about the pivot (1). This causes electrical contacts to be engaged so as to change the gears within the gearbox.

Description

MECHANICAL CONVERTER OF A CIRCULAR MOVEMENT INTO

  PENDULAR ALTERNATIVE MOVEMENT, ESPECIALLY APPLICABLE TO

SEQUENTIAL GEARBOXES

  The present invention relates to a mechanical converter of a circular movement of amplitude y around a driving pivot, in a pendular reciprocating movement in the same plane around a driven pivot of a rod otherwise called actuator, which can oscillate around said pivot at a given angle, symmetrically on either side of a forced rest position which aligns the actuator in the direction of the pivot leading along the straight line passing through the two pivots; this converter particularly interests the control of the selectors of a sequential gearbox in I in that, by a rotation in one direction and on one revolution (y = 2 x) at most, it causes a tilting of the actuator, c 'ie the gearbox selector, in one direction from its rest position to a first working position of amplitude equal to +0/2 then return of the selector to its initial rest position; conversely, by inverting the rotation at any time, it causes the selector to switch in the opposite direction from its rest position to a second opposite working position on one turn or at least a fraction of a turn, d 'amplitude - 0/2, followed by

  return to the initial rest position.

  The control of sequential gearbox selectors arises particularly in the field of motorcycles and more especially still in the field of karting; indeed, the speed changes on a kart are done manually thanks to a knob located near the steering wheel with the major drawback that this system forces the driver to release the steering wheel with one hand to select a new speed; As for motorcycles, we know that today the selection is generally made on foot, that is to say in a very manual way undoubtedly requiring good dexterity of the driver. In addition, the very position of the selector is generally uncomfortable and implements a relatively long movement -2- for the passage of a gear, which can create a certain insecurity for the driver. Finally, we know well the false gear changes resulting for example from a simple vibration of the selector creating a new difficulty for the same driver. We were therefore led to look for a mechanical movement converter capable of solving at least the list of the aforementioned drawbacks and incidentally providing the user with safety, comfort and time savings in the shifting of gears, hitherto unequaled. This mechanical converter, of a circular movement of amplitude y around a pivot leading in a pendulum reciprocating movement in the same plane around a pivot driven by a rod called actuator, which can oscillate around said pivot at a predetermined angle , symmetrically on either side of a forced rest position aligning the actuator in the direction of the pivot leading along the straight line passing through the two pivots, designed so that one rotation in one direction and at most on one revolution (y = 2 a) causes the actuator to tilt in one direction from its rest position to a working position of amplitude equal to +0/2 then return to the rest position, or vice versa, so that a reversal of rotation at any time, drives the actuator in the opposite direction from its rest position to an opposite working position, of amplitude -0/2, then on a revolution or a fraction of a revolution in the rest position, is remarkable in that that it comprises a first control rod coupled perpendicularly on one side to the driving pivot and articulated on the other at one end of a second intermediate rod which can move in a different plane although parallel to that of the control rod and in that the free end of the intermediate link is coupled to the free end of the actuator by means creating a punctual connection of intermittent positive support pushing said actuator from

  its rest position to a working position,

  beyond which said actuator returns by itself to its rest position whatever the subsequent movement of the control, either in the same direction to bring the actuator to each same turn in the same working position, or in the opposite direction to bring it each turn from its rest position to the opposite working position, or even to position itself at a standstill, that is to say in neutral where the control rod is aligned on the two pivots. It is easy to understand all the advantages of such a converter, in particular for its applications on the motorbike or in the kart for controlling the sequential I-boxes; it suffices in fact to associate the converter with a drive of the electric geared motor type controlling the circular movement of the driving pivot and therefore of the main and intermediate links which come to drive as will be said in detail below, the actuator of the converter playing the role of selector of the sequential box. According to a particularly advantageous embodiment of this application to go-karting or on a motorbike, the electric control of the selector can be obtained by two push-button switches near the foot or the hand of the user, the first controlling the gearmotor so that actuates the pivot leading on a turn in one direction to increase the speeds, the second contactor actuating in the other direction and on a revolution to lower the speeds, the assembly being associated with a position sensor located on said pivot, sensor which is also advantageously used to cut opportunely

  engine power during gear changes.

  Naturally other gear change systems for kart or motorcycle exist; but all of them use electromagnet techniques or more sophisticated systems using hydraulics or pneumatics. All these devices nevertheless have in common the major disadvantage of an often too heavy weight and above all reliability problems which we all measure.

  the consequences in sports competitions in particular.

  Other advantages will emerge even better from the -4-

  description which will be given below of a converter

  in accordance with the invention applied to the control of a sequential I-type gearbox, as an example undoubtedly preferred, but in no way limiting other applications of the invention and this, with reference to the accompanying drawings in which: - Figure 1 is a front view and in elevation of the mechanical movement converter according to the invention according to a variant with vertical actuator on which is also shown schematically the control by electric geared motor controlled by a straight servo R / left L, - figure 2 represents in six schematic steps numbered 2.1 to 2. 6, the kinematics of the converter of figure 1 and more especially the angular displacement of the actuator for a turn of the control, - figure 3 is a diagrammatic representation on a larger scale of a particular variant of the converter allowing the actuator to tilt in one direction or the other, ie pa r electric control,

either manually.

  In accordance with FIGS. 1 and 2, the mechanical converter making it possible to transform the circular movement of amplitude y around a driving pivot 1 extending perpendicularly above a plane P, into an alternating pendulum movement in the same plane P around a second driven pivot 2 of a slender element such as a rod otherwise called an actuator 3 which can oscillate in a plane parallel to P around said pivot 2 at a predetermined maximum angle, symmetrically on either side of a forced rest position, aligning the actuator 3 in the direction of the driving pivot 1 along a straight line V passing through the two pivots 1 and 2, is designed so that a rotation of the driving pivot 1 in a direct direction d or indirect i, and on a maximum of one revolution, that is to say for y = 2z, causes the actuator 3 to tilt in one direction, from its rest position along the line V to a first amplitude working position +0/2 followed by a reminder - 5 - automa tick of the actuator 3 in its rest position V or, conversely, designed so that an inversion of the rotation at any time results in a revolution or a fraction of a revolution, said actuator 3 in the opposite direction from its rest position V up to a second opposite working position of amplitude +0/2 followed by an automatic return of said actuator 3 to its rest position along V; for this purpose, the converter comprises a first control link 4 coupled perpendicularly on one side to the driving pivot 2 and articulated on the other at one end of a second intermediate link 5 which can move in a different plane although parallel to P , the other end of the intermediate link 5 being coupled to the free end of the actuator 3 by a connecting piece comprising a fork 6 with two branches 7 normally symmetrical in general U shape, secured to the center of its base 61 at the end of the actuator 3 flat in the plane of oscillation of said actuator 3 or in a parallel plane cooperating by means of a cylindrical stop 8 extending perpendicularly above and at the end of the intermediate link 5 to partially roll on the internal faces of the fork 6 during the

movement conversion.

  Referring to Figures 2, it will now be detailed the operation of the converter according to the invention shown in a very simplified manner for better readability of the drawings, according to a particular embodiment putting the actuator 3 in a vertical position, capable of oscillating in the plane P around the pivot 2, to the left and to the right of the rest position materialized by the line V: In FIG. 2.1, the converter is shown in stable rest position, that is to say that the link 4 is stopped vertically upwards along the right line V, the intermediate link 5 articulated to the control link 4 by a hinge 50 also arranged on the right line V above the pivot 1, is - 6 exactly superimposed on the fixed link 4; naturally the link 5 can oscillate freely around the joint 50 on either side of the. line V; it will be noted that this particular relative arrangement of the rods 4 and 5 represents the neutral point (PM) of the converter; at this time, the actuator 3 is in the vertical rest position along the line V; the branches 7 of the fork 6 mounted at the free end of the actuator 3 come from either side of the cylindrical stop 8 so that said stop cannot escape from the space between the two branches 7 during a natural oscillation of the link

  intermediate 5 around its articulation 50 which has remained fixed.

  According to other embodiments of the fork 6, the two branches 7 are inclined symmetrically towards one another and can even come to meet at their ends to come completely surround the cylindrical stop 8 which is then trapped inside a connecting piece 6 'closed in the general shape of a trapezoid or isosceles triangle as shown in dotted lines

in Figure 2.1.

  In accordance with FIGS. 2.2 to 2.6, the pendulum movement of the actuator 3 will now be studied by the rotation of the control rod 4 around one turn around the driving pivot 1: In FIG. 2.2, the relative position of the mechanism is shown when pivot 1 made a

  rotation y of about 1/3 of a turn in the direct direction (that is

  ie clockwise); during this movement, the actuator 3 remained vertical in the fixed rest position; on the other hand, the gearmotor driving the pivot 1 only had to overcome the inertias to shift the connecting rods 4 and 5 from the aligned position (figure 2.1) to the position of first contact of the stop 8 with the bottom 61 of the fork 6 , with the double consequence that the starting of this engine was practically empty and that it is at its maximum torque at the moment of starting to produce its efforts on the actuator 3. At this instant, the 7- cylindrical stop 8 resting on the bottom 61 of the fork 6 comes in rolling to move on the left of FIG. 2.2 until contact with the left branch 7 constituting an articulated anchor point for the connecting rod 5 which thus comes into positive contact with the actuator 3. In order to facilitate this progression of the link 5 bearing on the internal base 61 of the fork 6, provision has been made in a particular embodiment of the converter to give a concave shape to this internal base 61; advantageously and to avoid unnecessary rotations on the hinge axis 50 between the links 4 and 5, we choose to give this base the shape of an arc centered on the leading pivot 1 of radius r equal to the distance between said pivot 1 and said

  internal base 61 when the actuator 3 is at rest.

  According to the representation of figure 2.3 if one continues the movement around the pivot 1 in the direct direction (clockwise) one is then in the configuration of positive support between the stop 8 and the actuator 3 which begins to rock around pivot 2 on the left with respect to line V; at this moment, the gearmotor is at its maximum speed and the transmitted torques are also at maximum since the axes of the connecting rods 4 and 5 on the one hand, and the axes of the connecting rod and of the actuator 3 on the other hand are practically perpendicular with the double effect of a maximum torque transmission, and of a preservation in particular of the pivot 2 of the actuator 3 since the forces between axes are practically zero in this configuration. A person skilled in the art will know how to calculate the lengths of the links 4 and 5 as a function of the length of the actuator 3 in order to maintain as long as possible an angulation between the links as close as possible to 90 to optimize the transmission.

some efforts.

  In accordance with Figure 2.4 when the movement continues in the direct direction, the rods 4 and 5 eventually align, that is to say that the joint 50 and the axis of the stop 8 are aligned with the pivot 1 determining by their respective length as a function of the -8 length of the actuator 3 the maximum tilting angle of the same actuator 3 relative to the rest line V; naturally 'this maximum tilt angle left on

Figure 2.4 will correspond to +0/2.

  In accordance with Figure 2.5, the rotational movement around the pivot 1 always continues in the same direct direction and the angle of the links 4 and 5 now becomes obtuse to a position, depending on the geometry of all the links 4 and 5 and the length of the actuator 3, from which the intermediate link 5 can no longer impose a positive contact on the stop 8 located at the commissure of the branch 7 with the bottom 61 of the fork 6, which allows the actuator to find its own freedom of oscillation around the driven pivot 2 and to automatically resume the middle rest position along the straight line V by means of a simple helical spring 9 mounted in a known manner on the pivot 2

actuator 3.

  It will be observed here that the intermediate link 5 regains its natural oscillation allowing the actuator 3 to return freely to the rest position while the link 4 has still not completed its complete turn of rotation around the pivot 1. This link 4 may therefore continue its course freely and without load either to find the vertical along V and stop in neutral (PM) as in Figure 2.1, or continue in the same direct direction and reproduce a new tilting of the actuator 3 according to a maximum angle of +0/2, or finally reverse its movement, that is to say return following a rotation in the indirect direction as shown in Figure 2.5 in dotted lines (the references on the drawings in this situation are awarded) ; in the latter case, the converter symmetrically reproduces the detailed operation with respect to FIG. 2.2 until the cylindrical stop 8 ′ comes into contact with the commissure of the branch 7 ′ with the bottom 61 of the fork 6, starting from what positive forces are transmitted to the actuator 3 which can tilt to the right - 9 - of Figure 2.5 around the driven pivot 2 at a maximum angle -0/2 with subsequent return thanks to a spring 9 '

  operating like spring 9 but in reverse.

  In accordance with Figure 2.6, the last position of the converter is shown after a full revolution of the pivot leading 1 (y = 2 t), this position being naturally identical to that which the whole converter had in

Figure 2.1.

  According to a preferred embodiment of the invention, the mechanical movement converter which has just been described is directly applicable to the control of a sequential I-gearbox traditionally fitted to most motorcycles and especially karts and in particular the

competition karts.

  In accordance with FIG. 1, there is shown in the vertical position the selector of a sequential gearbox coming in place of the actuator 3 pivoting around the axis 2 of the sequential gearbox thanks to its terminal fork 6 cooperating with a cylindrical stopper 8 creating an intermittent punctual connection with the intermediate link 5 articulated to the control link 4 rotated around the driving pivot 1 by a motor 10 advantageously coupled to a reduction gear 11 in order to reduce the bulk and the weight of

all.

  For example, if the reduction between the motor and the reduction gear is equal to 10, the center distance between pivots 1 and 2 is 130 mm, the length of the control rod 4 between pivot 1 and articulation 50 is 25 mm and the length of the intermediate link 5 between the joint 50 and the axis of the stop 8 is 40 mm, if finally, the length of the actuator counted from the driven pivot 2 to the base 61 of the fork 6 is 100 mm, then for a complete revolution of the driving pivot 1, the selector 3 can oscillate around its central rest position of + or - 25, which is sufficient to raise or lower the speeds of the gearbox sequential in I controlled by selector 3; in this application the

- 10 -

  electric control of the selector 3 is obtained by two push-button switches L, R placed close to the user, for example on the steering wheel of the kart or on the handlebars of the motorcycle: a first contactor L makes it possible to control the geared motor 10,11 so that it actuates the pivot leading 1 on a revolution in one direction, for example in the direct direction, to increase the speeds; a position sensor 12 mounted on the driving pivot 1 for example, will make it possible to check that the control link 4 does indeed make a full turn in the direct direction when the push button L is pressed. Thus the link 4 starting from the point dead will necessarily make a revolution until the next dead center then will stop waiting for a new pulse on one or the other of the contactors L, R. This position sensor 12 could for example be a potentiometer making it possible to fix the geometric position of the rod 4 with sufficient precision; it will be observed here that it is of little importance to have a high precision since it has been seen that there was a relatively large dead zone of training, precisely before and after the position

from neutral.

  Naturally, the second press button R will activate the gearmotor in the opposite direction, the position sensor 12 operating in the same way to stop the gearmotor after a complete revolution of the driving pivot 1. A servo card 13 is provided for. one part to prohibit the operation of a pusher when the other is actuated and manage the position setpoints from the sensor 12 to transmit power from a

  battery 14 to the drive motor 10.

  Of course, the card 13 is also designed so that with each instruction coming from one or the other of the push buttons L or R, one causes not only the passage from one speed to another, but also that the motor power is cut during this operation. With such a device associated with the previous mechanism, it was able to measure that the time required for a gear change was less than more than 3 tenths of

- 11 -

  second compared to a manual shift which also causes a substantial drop in engine speed; this converter according to the invention, which simultaneously activates the ignition cut-off and the engagement of the gear in a maximum time of 1 tenth of a second is particularly advantageous when used in competition which requires a very large number of passages

speeds per lap.

  In accordance with FIG. 3, a particularly advantageous variant of the invention will now be described when the converter is used for the control of sequential gearboxes. It may be advantageous in certain circumstances to be able to manually select a desired speed while the motorcycle or the kart is equipped with an electric selector as described above. The selector 3 being in the rest position in neutral must now be able to be driven to the left or to the right of the line V according to the manual or foot control conventionally existing on go-karts or motorcycles: in FIG. 3, diagrammatically shown the selector 3 according to its three main positions: on the right in solid lines, the actuator 3 is tilted by an angle of -0/2 to descend a speed, on the left and in dotted lines, the selector 3 is tilted by maximum angle of 0/2 to increase the gears, and in the middle along the line V, the selector 3 is in neutral rest position also called neutral. As seen in Figure 3, when the selector 3 is in the maximum tilt position, left or right in Figure 3, the intermediate link 5 is driven by the actuator in the same way, left or right , by a rotation about the axis 50 which is fixed since the control rod 4 has in principle remained fixed in neutral. It is therefore understandable that the link 5 of insufficient length to allow tilting to the left or to the right by an angle equal to 0/2 of the actuator 3, will tend either to escape from the fork 6 or to limit the tilting

- 12 -

  actuator 3, resulting in the impossibility

  to activate the sequential gearbox.

  According to the proposed variant, the fork 6 is replaced by a connecting piece 15 having the general shape of an hourglass on the internal edges of which the cylindrical stop 8 at the end of the link 5 can move without being ejected to allow the necessary tilting of the actuator 3 as shown on the left and on the right of FIG. 3. According to a preferred embodiment of this variant, the connecting piece 15 is obtained from two forks 6 mounted head to tail by the ends of their branches 7, the distance between them is at least equal to the diameter of the cylindrical stop 8 in order to allow it to move freely from a higher position as shown on the left and on the right in FIG. 3 (working position of the actuator 3 ) to a central position practically in the center of the lower fork as shown in thin broken lines in FIG. 3. This rest position can be at any time used by a rotation of the link 4 around the pivot 1 when the selection is done automatically, the stop 8 can then join the right or left commissure of the branches 7 with the bottom 61 of the lower part of the connecting piece 15 to transmit the forces of the geared motor 10,11 in a manner very similar to what has been detailed in the

basic variant.

  Naturally, the person skilled in the art will, as for the basic variant, be able to determine the optimal dimensions for producing the connecting piece 15 according to the tilt angle 0 of the actuator which naturally depends on the

type of sequential box.

  It is understood that all that has been described previously in relation to an actuator or a selector 3 in the vertical position, would remain fully valid for a selector or an actuator in the horizontal position. In addition, it will be observed that taking into account the mechanism present, the size of the mechanism does not matter

- 13 -

  subject to keeping the same proportion in the lengths between moving parts, that is to say rods 4.5 and actuator 3. This important characteristic of the invention thus makes it possible to minimize the piloting of a selector box, which again reduces the size and therefore the weight

of the on-board device.

- 14 -

Claims (8)

  1 - Mechanical converter of a circular movement of amplitude y around a driving pivot (1) into a reciprocating pendulum movement in the same plane P around a driven pivot (2) of a rod called actuator (3) , able to oscillate around said pivot at a predetermined angle, symmetrically on either side of a forced rest position aligning the actuator (3) in the direction of the driving pivot (1) along the straight line V passing through the two pivots ( 1,2), designed so that a rotation in one direction and a maximum of one revolution (y = 2 x) causes the actuator (3) to tilt in one direction from its rest position to a position of amplitude work equal to +0/2 then return to the rest position, or vice versa, so that an inversion of the rotation at any time, results in a revolution or a fraction of a revolution, the actuator ( 3) in the opposite direction from its rest position to an opposite working position, of amplitude -0/2 then recall to the rest position, characterized in that it comprises a control rod (4) coupled perpendicularly on one side to the driving pivot (1) and articulated on the other at one end of an intermediate rod (5) which can move in a different plane although parallel to the plane P and in that the free end of the intermediate link (5) is coupled to the free end of the actuator (3) by means creating a punctual connection of positive intermittent repelling support said actuator (3) from its rest position to a working position, beyond which said actuator (3) returns by itself to its rest position regardless of the subsequent movement of the control, either in the same direction to bring each new turn, the actuator (3) in the same working position, either in the opposite direction to bring it each turn from its rest position to the opposite working position, or again for take a stand at neutral (PM) o the links (4) and (5) are aligned with the two pivots. - 15 -   2 - Mechanical movement converter according to the preceding claim characterized in that the intermittent punctual connection between the free ends of the intermediate link (5) and the actuator (3) is obtained by the cooperation of a cylindrical stop (8) extending perpendicularly above and at the end of said link (5) and of a fork (6) with two branches (7) in the general shape of U secured in the plane P of oscillation or in a parallel plane, by its base (61) and in its center at the free end of the actuator (3) to serve as a raceway for the cylindrical stop (8) which can thus move freely   on the internal faces of the fork (6).   3 - Mechanical movement converter according to claim 2 characterized in that the height of the legs (7) of the fork (6) is such that when the control is in neutral (PM), the cylindrical stop (8) can not s '' escape from the interior of the fork (6) during a natural oscillation of the intermediate link (5) around its axis of articulation (50) to   the control rod (4) remained fixed.   4 - Mechanical movement converter according to claim 3 characterized in that the legs (7) of the fork (6) are inclined symmetrically towards each other until joining at their end to give the connecting piece (6 ') which results in a form   general of trapezium or isosceles triangle.   - Mechanical motion converter according to one   any one of claims 2 to 4 characterized in that   the internal base (61) of the fork (6) is concave advantageously in an arc centered on the driving pivot (1), of radius (r) equal to the distance between said pivot (1) and said internal base (61 ) when the actuator (3) is at rest.   6 - Mechanical motion converter according to one   any one of claims 2 to 5 characterized in that   the width of the internal base (61) of the fork (6) is chosen so that the force transmitted to the actuator (3) by - 16 -   the intermediate link (5) at the commissure of the branches (7) of the fork (6) is optimum while limiting the forces of the axles, that is to say by ensuring that the axes of said link (5) and the actuator (3) remain substantially perpendicular to the during exercise.   7 - Mechanical motion converter according to one   any one of claims 2 to 6 characterized in that   the ends of the legs (7) of the fork (6) are at a distance at least equal to the diameter of the cylindrical stop (8) and are extended outwards and in the same plane as the first by a second fork (15) generally identical to the first, head to tail mounted to accommodate the cylindrical stop (8) of the intermediate link (5) oscillating freely around its articulation (50) when the actuator (3) is mu directly, other than by the   control remained in the neutral position.   8 - Application of the mechanical converter   movement according to any one of the claims   previous to the sequential I-gearbox control in which the actuator (3) corresponds to the gear selector and the circular movement of the driving pivot (1) driving the links (4,5) is obtained by a set   gear motor (10,11), electrically controlled.   9 - Application of the mechanical movement converter according to the preceding claim characterized in that the electrical control of the selector (3) is obtained by two push-button contactors (L, R) near the user, one controlling the gearmotor ( 10,11) so that it actuates the driving pivot (1) on one revolution in one direction to increase the speeds, the other in the other direction and on a revolution, to descend them, in association with a position sensor (12) located on said pivot (1) coupled to conventional means for cutting off the power to the motor when changing gears.   - Application of the mechanical motion converter according to claim 9 in combination with the - 17 -   claim 7 characterized in that the control of the gear selector can be indifferently and at any time carried out by a conventional manual control or by   electric control of the selector.